1. Field of the Invention
The present invention relates to a light emitting diode (LED) package, and more particularly, to an LED package including a plurality of different (or the same) LED chips and different fluorescent material layers formed at the LED chips according to the characteristics of light emitted from the LED chips for providing light having high intensity and good color rendering characteristics.
2. Description of the Related Art
In general, light emitting diodes (LEDs) are widely used in packaged states for various display devices and as light sources owing to their good monochromic peak wavelengths, good optical efficiency, and small size. Particularly, many efforts have been made to develop LEDs that can be used as a highly efficient and high-power light source of lighting equipment and a backlight of a display device.
FIG. 1 is a cross-sectional view illustrating an LED package 10 of the related art.
Referring to FIG. 1, the LED package 10 of the related art includes a package body 11 and a LED chip 17. The package body 11 includes a mounting part 12 for mounting the LED chip 17 thereon, and a reflective surface 15 formed on a sidewall surrounding the mounting part 12. Lead electrodes 13 and 14 are arranged on the bottom of the mounting part 12. The LED chip 17 disposed in the LED package 10 may be electrically connected to the lead electrodes 13 and 14 using wires. The LED chip 17 is sealed with a resin packing part 19 formed of a resin such as an epoxy resin and a silicon resin.
In a most common method for constituting a white light emitting device using an LED, a yellow fluorescent material is applied to a blue LED chip. To obtain light having a desired wavelength such as white light using a yellow fluorescent material as described above, fluorescent material particles are dispersed in the resin packing part 19. For example, the resin packing part 19 may be formed by dispersing a yellow fluorescent material containing yttrium aluminum garnet (YAG) into a silicon resin.
Besides the yellow fluorescent material containing YAG, other fluorescent materials containing terbium aluminum garnet (TAG) or silicate can be used. Particularly, YAG or TAG containing materials are good fluorescent materials using the light emitting characteristics of cerium (Ce) and blue light as excitation light.
Although bright (or intensive) light can be obtained using such a blue LED chip coated with a yellow fluorescent material, the color rendering characteristics of the LED chip are poor.